1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method of reporting by a user equipment in a wireless communication system, and an apparatus supporting the method.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
Minimization of driving tests (MDT) is performed by venders for coverage optimization by using a user equipment (UE) instead of using an automobile. The coverage varies depending on a location of a base station (BS), a deployment of neighboring buildings, and a user's usage environment. Therefore, it is required for the vender to periodically perform the driving test, and a lot of costs and resources are consumed. The MDT is used by the vender to optimize a network by using the UE.
The MDT can be classified into a logged MDT and an immediate MDT. According to the logged MDT, after performing the MDT measurement, the UE delivers a logged measurement to the network at a particular time. According to the immediate MDT, after performing the MDT measurement, the UE delivers the measurement to the network when a report condition is satisfied. The logged MDT performs the MDT measurement in a radio resource control (RRC)_idle mode, and the immediate MDT performs the MDT measurement in an RRC_connected mode.
The vender can synthesize MDT measurements received from several UEs to create a coverage map which indicates a distribution of quality of service and whether a service is available across an overall area in which the vender provides a service, and thus can utilize the coverage map for a network operation and optimization. For example, when a coverage problem of a specific area is reported from the UE, the vender can increase transmit power of the BS which provides a service of the area to expand coverage of a corresponding cell.
A wireless communication system may have an environment in which one vender manages a plurality of public land mobile networks (PLMNs), or a plurality of venders manage the plurality of PLMNs. Regarding the PLMN, the UE may receive a PLMN list related to an MDT execution, and the UE may perform measuring and logging on the basis of the PLMN list. Meanwhile, a new PLMN list may be provided while the UE performs the MDT. In this case, there may be a problem regarding a validity of a log entry which is measured in advance and logged by the UE.